Conventionally, a ceramic heater formed by burying a heating element in a heater plate made of ceramic is used for heating a wafer in a process of manufacturing a semiconductor, for example, in CVD processing and etching. The ceramic heater is formed by burying metal, serving as the heating element, such as molybdenum having a heat resistance in the ceramic base, molding the ceramic base, and then heating and sintering the molded ceramic base at a high temperature. However, there is a problem that conductivity non-uniformly deteriorates since the buried metal reacts with carbon content in powder and is carbonized during the sintering, and a temperature distribution occurs in the heater plate.
On the other hand, a technique is disclosed in which a metallic heating element buried in a ceramic base is wound by a metal member made of the same material in a non-conduction state, and the ceramic base in which the heating element is buried is sintered to carbonize or oxidize the metal member prior to the heating element, thereby providing a ceramic heater having a high soaking property (for example, see Patent Literature 1).